My only other thought here is; this network sits on Regus (Serviced Office) Network, they provide a Public WAN IP for us to sit behind with open access. I am wondering if they have NAT enabled thus screwing up our ports inbound/outbound.

and this foot note:
Important note: If the other party uses MXP series TelePresence, then the ports differ, for example RTP media ports for MXP series are UDP 46000-49000 and not 2326-2485. So you need to know about the other party equipment to open the required ports in the firewall.